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Old 05-30-2023, 01:01 AM   #4 (permalink)
Ecky
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Quote:
Originally Posted by ttrainxl View Post
Good info. Thank you. Does the old APEXi VAFC control VTEC crossover? I used to have one of those about 20 years ago that I wanted to use in my GSR and I never installed it. I wonder if I could bump VTEC crossover up to maybe 3000 rpm (think P07 has it cross at 2500) and not swap out the final drive or a whole transmission.

I guess sticking with a stock P07 ECU is probably the easiest way to go.
Never used one, but I assume it would work. It's worth noting, the crossover point is not just RPM dependent, but also load dependent - at part throttle it'll cross over higher. For the best powerband you'd want to set VTEC crossover to whatever point makes it imperceptible, but setting it higher (where you get a noticeable increase in power) would probably make cruising more frugal, as you'd be valve-limiting the air into the motor and cutting pumping losses. I doubt the difference would be large though. I wonder if the P07 allows lean burn after VTEC?

Low hanging fruit with economy will be with a taller FD, from my experience. Going from a ~4.4 to a ~3.4 FD in my Insight build was worth something like 6-8mpg while cruising.

Regardless, the challenge after a head swap will be to get knock under control. Whatever you do, you'll need to get fueling somewhat close, and you'll need to pull a couple degrees of timing, and likely up your octane.
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